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<title>&lt;math.h&gt;</title>
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The Single UNIX &reg; Specification, Version 2<br>
Copyright &copy; 1997 The Open Group

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<h4><a name = "tag_000_007_505">&nbsp;</a>NAME</h4><blockquote>
math.h - mathematical declarations
</blockquote><h4><a name = "tag_000_007_506">&nbsp;</a>SYNOPSIS</h4><blockquote>
<pre><code>

#include &lt;math.h&gt;
</code>
</pre>
</blockquote><h4><a name = "tag_000_007_507">&nbsp;</a>DESCRIPTION</h4><blockquote>
The
<i>&lt;math.h&gt;</i>
header provides
for the following constants.
The values are of type
<b>double</b>
and are accurate within the precision of the
<b>double</b>
type.
<dl compact>

<dt>M_E<dd>
Value of <i>e</i>

<dt>M_LOG2E<dd>
Value of log<small><sub>2</sub></small><i>e</i>

<dt>M_LOG10E<dd>
Value of log<small><sub>10</sub></small><i>e</i>

<dt>M_LN2<dd>
Value of log<small><sub>e</sub></small>2

<dt>M_LN10<dd>Value of log<small><sub>e</sub></small>10

<dt>M_PI<dd>
Value of <sub><img src="../images/pi.gif"></sub>

<dt>M_PI_2<dd>Value of <sub><img src="../images/pi.gif"></sub>/2

<dt>M_PI_4<dd>Value of <sub><img src="../images/pi.gif"></sub>/4

<dt>M_1_PI<dd>Value of 1/<sub><img src="../images/pi.gif"></sub>

<dt>M_2_PI<dd>
Value of 2/<sub><img src="../images/pi.gif"></sub>

<dt>M_2_SQRTPI<dd>Value of 2/ <sub><img src="../images/sqrt2.gif"><img src="../images/pi.gif"></sub>

<dt>M_SQRT2<dd>
Value of <sub><img src="../images/sqrt2.gif"></sub>2

<dt>M_SQRT1_2<dd>
Value of 1/<sub><img src="../images/sqrt2.gif"></sub>2

</dl>
<p>
The header defines the following symbolic constants:
<dl compact>

<dt>MAXFLOAT<dd>
Value of maximum non-infinite single-precision floating point number.

<dt>HUGE_VAL<dd>
A positive
<b>double</b>
expression, not necessarily representable as a
<b>float</b>.
Used as an error value returned by the mathematics library.
HUGE_VAL evaluates to positive infinity on systems supporting 
the ANSI/IEEE&nbsp;Std&nbsp;754:1985 standard.

</dl>
<p>
The following are declared as functions and may also be defined
as macros.
Function prototypes must be provided for use with an ISO C
compiler.
<pre>
<code>
double <a href="acos.html">acos</a>(double);
double <a href="asin.html">asin</a>(double);
double <a href="atan.html">atan</a>(double);
double <a href="atan2.html">atan2</a>(double, double);
double <a href="ceil.html">ceil</a>(double);
double <a href="cos.html">cos</a>(double);
double <a href="cosh.html">cosh</a>(double);
double <a href="exp.html">exp</a>(double);
double <a href="fabs.html">fabs</a>(double);
double <a href="floor.html">floor</a>(double);
double <a href="fmod.html">fmod</a>(double, double);
double <a href="frexp.html">frexp</a>(double, int *);
double <a href="ldexp.html">ldexp</a>(double, int);
double <a href="log.html">log</a>(double);
double <a href="log10.html">log10</a>(double);
double <a href="modf.html">modf</a>(double, double *);
double <a href="pow.html">pow</a>(double, double);
double <a href="sin.html">sin</a>(double);
double <a href="sinh.html">sinh</a>(double);
double <a href="sqrt.html">sqrt</a>(double);
double <a href="tan.html">tan</a>(double);
double <a href="tanh.html">tanh</a>(double);
double <a href="erf.html">erf</a>(double);
double <a href="erfc.html">erfc</a>(double);
double <a href="gamma.html">gamma</a>(double);
double <a href="hypot.html">hypot</a>(double, double);
double <a href="j0.html">j0</a>(double);
double <a href="j1.html">j1</a>(double);
double <a href="jn.html">jn</a>(int, double);
double <a href="lgamma.html">lgamma</a>(double);
double <a href="y0.html">y0</a>(double);
double <a href="y1.html">y1</a>(double);
double <a href="yn.html">yn</a>(int, double);
int    <a href="isnan.html">isnan</a>(double);
double <a href="acosh.html">acosh</a>(double);
double <a href="asinh.html">asinh</a>(double);
double <a href="atanh.html">atanh</a>(double);
double <a href="cbrt.html">cbrt</a>(double);
double <a href="expm1.html">expm1</a>(double);
int    <a href="ilogb.html">ilogb</a>(double);
double <a href="log1p.html">log1p</a>(double);
double <a href="logb.html">logb</a>(double);
double <a href="nextafter.html">nextafter</a>(double, double);
double <a href="remainder.html">remainder</a>(double, double);
double <a href="rint.html">rint</a>(double);
double <a href="scalb.html">scalb</a>(double, double);
</code>
</pre>
<p>
The following external variable is defined:
<pre>
<code>
extern int signgam;
</code>
</pre>
</blockquote><h4><a name = "tag_000_007_508">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_007_509">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_007_510">&nbsp;</a>SEE ALSO</h4><blockquote>
<i><a href="acos.html">acos()</a></i>,
<i><a href="acosh.html">acosh()</a></i>,
<i><a href="asin.html">asin()</a></i>,
<i><a href="atan.html">atan()</a></i>,
<i><a href="atan2.html">atan2()</a></i>,
<i><a href="cbrt.html">cbrt()</a></i>,
<i><a href="ceil.html">ceil()</a></i>,
<i><a href="cos.html">cos()</a></i>,
<i><a href="cosh.html">cosh()</a></i>,
<i><a href="erf.html">erf()</a></i>,
<i><a href="exp.html">exp()</a></i>,
<i><a href="expm1.html">expm1()</a></i>,
<i><a href="fabs.html">fabs()</a></i>,
<i><a href="floor.html">floor()</a></i>,
<i><a href="fmod.html">fmod()</a></i>,
<i><a href="frexp.html">frexp()</a></i>,
<i><a href="hypot.html">hypot()</a></i>,
<i><a href="ilogb.html">ilogb()</a></i>,
<i><a href="isnan.html">isnan()</a></i>,
<i><a href="j0.html">j0()</a></i>,
<i><a href="ldexp.html">ldexp()</a></i>,
<i><a href="lgamma.html">lgamma()</a></i>,
<i><a href="log.html">log()</a></i>,
<i><a href="log10.html">log10()</a></i>,
<i><a href="log1p.html">log1p()</a></i>,
<i><a href="logb.html">logb()</a></i>,
<i><a href="modf.html">modf()</a></i>,
<i><a href="nextafter.html">nextafter()</a></i>,
<i><a href="pow.html">pow()</a></i>,
<i><a href="remainder.html">remainder()</a></i>,
<i><a href="rint.html">rint()</a></i>,
<i><a href="scalb.html">scalb()</a></i>,
<i><a href="sin.html">sin()</a></i>,
<i><a href="sinh.html">sinh()</a></i>,
<i><a href="sqrt.html">sqrt()</a></i>,
<i><a href="tan.html">tan()</a></i>,
<i><a href="tanh.html">tanh()</a></i>,
<i><a href="y0.html">y0()</a></i>.
</blockquote><hr size=2 noshade>
<center><font size=2>
UNIX &reg; is a registered Trademark of The Open Group.<br>
Copyright &copy; 1997 The Open Group
<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]

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